Hello, I am am looking for the rectangular Fuel Economy Meter (working on vacuum) for a 75-76 Oldsmobile 88/98 Instrument panel and the Toronado also had them.
I believe Chevy Caprice/Impala also had them on those years but I'm not sure if it is the same size? Thanks and regards

 

It'll have to come from a 74-76 88/98/Toronado and IIRC you have to change out the entire speedometer cluster. Your best bet is to find someone parting out a car that has it and get the whole thing. They were common on Ninety Eights.